266261566 has 4 divisors (see below), whose sum is σ = 399392352. Its totient is φ = 133130782.

The previous prime is 266261563. The next prime is 266261579. The reversal of 266261566 is 665162662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 665162662 = 2 ⋅332581331.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266261563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66565390 + ... + 66565393.

It is an arithmetic number, because the mean of its divisors is an integer number (99848088).

Almost surely, 2^266261566 is an apocalyptic number.

266261566 is a deficient number, since it is larger than the sum of its proper divisors (133130786).

266261566 is a wasteful number, since it uses less digits than its factorization.

266261566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133130785.

The product of its digits is 155520, while the sum is 40.

The square root of 266261566 is about 16317.5232802040. The cubic root of 266261566 is about 643.3334908916. Note that the first 3 decimals are identical.

The spelling of 266261566 in words is "two hundred sixty-six million, two hundred sixty-one thousand, five hundred sixty-six".